The present invention relates generally to an improved lamp or illuminating structure, and more specifically to a shade means for use in combination with a conventional illuminating lamp structure. The shade means of the present invention is adapted to transmit only a portion of incident tungsten filament radiation, with the balance being reflected internally so as to generate reflective and interference patterns within the structure, and specifically within the confines of the shade, and also for a limited distance outwardly of the open ends thereof.
In general, lamp shades have been transparent to limited degrees, but have tended to either absorb or otherwise handle incident radiation. For example, opaque or only partially translucent shades have been utilized wherein the incident radiation is absorbed or otherwise reflected to only a limited extent, with care being taken to provide decorative affects about the periphery of the lamp. Traditionally, these shade structures have been prepared from woven fabric, fibrous or cellulose base materials, or the like, and have generally not been fabricated from transparent substrates such as thin flexible films.
With the advent of thin transparent films such as, for example, stress-oriented polyethylene terephthalate films, it is practical to utilize these materials to achieve desired patterns with lamp structures. Specifically, these materials are desirable from the standpoint of strength, temperature stability, durability, ease of fabrication, and resistance to ordinary cleaners. It has now been learned that unusual patterns can be generated through the use of such a lamp by means of applying a metallized coating, partially transparent, and partially reflective, to a surface of the shade in order to achieve unusual patterns therewithin. In certain instances, it is desirable to utilize a dye coating in the film so as to provide a color to the reflected and transmitted radiation, with the color being, of course, readily detectable by the eye from either a point externally of the shade structure, or from a point adjacent and in viewing relationship through an open end. It has been found that the concept is useful in connection with shades disposed either on a vertical or horizontal axis, and including cylindrical or other shaped shades defining an enclosed zone.
The degree of transmission and the degree of reflection is, as previously indicated, in the range of from about 92% to 98% reflective for tungsten filament lamp radiation. More specifically, a film which is approximately 4% transmissive and 96% reflective has been found to be most desirable, with a range of from about 2% to 6% transmissive being generally preferred.